Influence of Substrate on Crystallographic Quality of AlGaN/GaN HEMT Structures Grown by Plasma-Assisted MBE

Wierzbicka, Aleksandra; Żytkiewicz, Z. R.; Sobanska, M.; Kłosek, K.; Łusakowska, E.

doi:10.12693/aphyspola.121.899

Cited by 11 publications

(4 citation statements)

References 8 publications

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“…This commercial software is based on Parratt theory. 27 This method allowed us to determine thickness of the layer, electron density and roughness of the sample's surface and interface. 28,29 It should be mentioned that this method allows the determination of the global roughness of the sample.…”

Section: Test Equipmentmentioning

confidence: 99%

<p>Zirconium Oxide Thin Films Obtained by Atomic Layer Deposition Technology Abolish the Anti-Osteogenic Effect Resulting from miR-21 Inhibition in the Pre-Osteoblastic MC3T3 Cell Line</p>

Seweryn¹,

Pielok²,

Ławniczak-Jabłońska³

et al. 2020

IJN

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The development of the field of biomaterials engineering is rapid. Various bioactive coatings are created to improve the biocompatibility of substrates used for bone regeneration, which includes formulation of thin zirconia coatings with pro-osteogenic properties. The aim of this study was to assess the biological properties of ZrO 2 thin films grown by Atomic Layer Deposition (ALD) technology (ZrO 2 ALD). Methodology: The cytocompatibility of the obtained layers was analysed using the mice preosteoblastic cell line (MC3T3) characterized by decreased expression of microRNA 21-5p (miR-21-5p) in order to evaluate the potential pro-osteogenic properties of the coatings. The in vitro experiments were designed to determine the effect of ZrO 2 ALD coatings on cell morphology (confocal microscope), proliferative activity (cell cycle analysis) and metabolism, reflected by mitochondrial membrane potential (cytometric-based measurement). Additionally, the influence of layers on the expression of genes associated with cell survival and osteogenesis was studied using RT-qPCR. The following genes were investigated: B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), p53 and p21, as well as osteogenic markers, i.e. collagen type 1 (Coll-1), osteopontin (Opn), osteocalcin (Ocl) and runt-related transcription factor 2 (Runx-2). The levels of microRNA (miRNA/miR) involved in the regulation of osteogenic genes were determined, including miR-7, miR-21, miR-124 and miR-223. Results: The analysis revealed that the obtained coatings are cytocompatible and may increase the metabolism of pre-osteoblast, which was correlated with increased mitochondrial membrane potential and extensive development of the mitochondrial network. The obtained coatings affected the viability and proliferative status of cells, reducing the population of actively dividing cells. However, in cultures propagated on ZrO 2 ALD coatings, the up-regulation of genes essential for bone metabolism was noted. Discussion: The data obtained indicate that ZrO 2 coatings created using the ALD method may have pro-osteogenic properties and may improve the metabolism of bone precursor cells. Given the above, further development of ZrO 2 ALD layers is essential in terms of their potential clinical application in bone regenerative medicine.

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Section: Test Equipmentmentioning

confidence: 99%

<p>Zirconium Oxide Thin Films Obtained by Atomic Layer Deposition Technology Abolish the Anti-Osteogenic Effect Resulting from miR-21 Inhibition in the Pre-Osteoblastic MC3T3 Cell Line</p>

Seweryn¹,

Pielok²,

Ławniczak-Jabłońska³

et al. 2020

IJN

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“…The crystallinity and phase composition of the layers were determined by X-ray diffraction (XRD) investigations. A Panalytical X'Pert Pro MRD diffractometer (Panalytical, Almelo, Netherlands) was used, equipped with: A X-ray tube generating radiation at a wavelength of 1.54056 Å, a hybrid two-bounce Ge (220) monochromator, and a Pixel detector [36]. Measurements were performed in two diffraction modes: in coplanar and non-coplanar Grazing Incidence X-ray diffraction (GIXRD) geometries [37,38].…”

Section: Measurements Equipmentmentioning

confidence: 99%

Structural and Electrical Parameters of ZnO Thin Films Grown by ALD with either Water or Ozone as Oxygen Precursors

et al. 2019

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Low temperature (at 100 • C and below) growth of ZnO thin films by atomic layer deposition (ALD) is demonstrated. Properties of the layers grown with two different oxygen reagents: ozone and water are compared. Diethylzinc (DEZ) was used as metal precursor. Electrical and structural properties of films obtained at several different growth temperatures, ranging from 50 • C to 250 • C were analyzed. It turned out that the film grown in the water-based process at 250 • C and all films grown with ozone have more ordered crystallographic structure with the privileged growth direction (001) perpendicular to the substrate than water-based samples grown in temperatures 100-200 • C. Higher free electron concentration at room temperature was observed for ozone-based samples grown at 100 • C and 150 • C in comparison to water-based samples obtained at the same growth temperature. Low value of resistivity in case of ozone-based samples grown at 100 • C is a promising result, however lower electron mobility requires further optimization.

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“…The simulated data are presented in Table . Oscillations on the reflectivity curves due to the CdO/MgO interfaces, commonly known as Kiessig fringes, are clearly visible on the XRR profiles. Their presence indicates the high quality of the interfaces and allows one to determine the thickness of the layers.…”

Section: Results and Discussionmentioning

confidence: 99%

Short-Period CdO/MgO Superlattices as Cubic CdMgO Quasi-Alloys

Przeździecka

Wierzbicka

Dłużewski

et al. 2020

Crystal Growth & Design

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New perspective cubic quasi-alloy {CdO/MgO} m short-period superlattices (SLs) were grown on r-plane sapphire substrates by plasma-assisted molecular beam epitaxy. The quality of crystals was characterized using high resolution X-ray diffraction and transmission electron microscopy (TEM) techniques. X-ray diffraction confirmed the cubic structure of the samples and the presence of peaks corresponding to the SLs with period ranging from 0.6 to 5 nm. Reciprocal space maps around the (200) and (412) Bragg reflections were collected to analyze the strain in the SLs layers with very high precision. Local lattice parameters were measured by digital processing of experimental HRTEM images. From TEM and small-angle X-ray, thicknesses and growth rates of individual layers of MgO and CdO have been extracted. We found that thicknesses of the CdO and MgO layers influence the measured band gap. Surface roughness parameters for SLs were obtained by both small-angle X-ray diffraction and atomic force microscopy study.

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Influence of Substrate on Crystallographic Quality of AlGaN/GaN HEMT Structures Grown by Plasma-Assisted MBE

Cited by 11 publications

References 8 publications

<p>Zirconium Oxide Thin Films Obtained by Atomic Layer Deposition Technology Abolish the Anti-Osteogenic Effect Resulting from miR-21 Inhibition in the Pre-Osteoblastic MC3T3 Cell Line</p>

<p>Zirconium Oxide Thin Films Obtained by Atomic Layer Deposition Technology Abolish the Anti-Osteogenic Effect Resulting from miR-21 Inhibition in the Pre-Osteoblastic MC3T3 Cell Line</p>

Structural and Electrical Parameters of ZnO Thin Films Grown by ALD with either Water or Ozone as Oxygen Precursors

Short-Period CdO/MgO Superlattices as Cubic CdMgO Quasi-Alloys

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